The present invention relates to rail anchor removal. More particularly, it relates to removal of rail anchors using a track renewal machine.
The rails of a railroad track are usually secured to cross ties by spikes driven into tie plates. These tie plates block lateral movement of the rails, i.e., movement that is transverse to the rail direction. Anchors are attached to the rails to secure the rails against longitudinal movement of the rails relative to the cross ties.
When a rail is to be replaced or renovated, the spikes which secure the tie plates and rail to the ties are first removed. The rail anchors, which often are drive-on anchors, then are removed from the rails. Often the anchors are removed from the rails using manual labor. Specifically, a person swings a sledge hammer against the drive-on anchors, driving the anchors from the base of the rail. This is very physically demanding and labor intensive.
Following the removal of the anchors, a track renewal machine with tie wagons in front of it travels along the section of rails where renewal is needed. The forgoing techniques have usually required removal of the anchors in advance of the tie wagons entering that section of the track.
The track renewal machine then uses rail threaders which move the rails vertically up from the ties (more specifically from the tie plates on the ties) and spreads the rails out horizontally sufficiently far that old ties may be lifted up without hitting the rails. Various other operations are commonly performed such as inserting new ties, distributing ballast around the new ties, and applying rail clips. Either the old rails (if in acceptable condition) or new rails are then laid on the new cross ties and are secured in place. As used herein, a track renewal machine shall includes machines which spread out rails such that ties may be lifted up from in between the rails and any machines having rail threaders thereon.
It will be understood, that if only the ties are to be replaced for a given section of track and the rails are not being replaced, a tie gang may be used. With a tie gang, the cross ties are removed from beneath the side of the rails, but without spreading the rails apart. This is a different process than the rail spreading track renewal discussed hereinabove.
Devices have been developed to remove anchors automatically and without the manual labor associated with sledge hammer removal. However, such devices have increased the complexity of the already complex series of operations used in rail spreading track renewal.
The following U.S. Patents and their issue dates are noted:
U.S. Pat. No. 4,903,611 Holley Feb. 27, 1990 PA1 U.S. Pat. No. 5,146,677 Holman et al. Sep. 15, 1992 PA1 U.S. Pat. No. 5,269,225 Bosshart et al. Dec. 14, 1993
The Holley Patent shows an anchor spreader apparatus and method for using with tie gangs.
The Holman Patent discloses a rail anchor remover mounted on a crane.
The Bosshart Patent shows an apparatus and method for applying rail clips and insulators.
None of these prior art devices have been found to be completely satisfactory.